The present invention relates to a hip joint prosthesis and more particularly to a femoral component of such prosthesis. U.S. Pat. No. 5,080,680, of which I am a co-inventor, discloses a femoral stem prosthesis with a preapplied cement mantle. A continuation-in-part application of such patent, namely, application Ser. No. 07/673,367, filed Mar. 22, 1991, discloses another embodiment in which the preapplied cement mantle has a series of interstices or openings in the preapplied cement mantle.
As disclosed in the above patent and continuation-in-part application, each of such prostheses is implanted in the intramedullary canal of the femur of a patient, normally with its distal end positioned in a centralizer which assures proper positioning of such distal end in the central area of the intramedullary canal. As is well-known in the field of implanting femoral prostheses, bone cement such as polymethylmethacrylate (PMMA) is normally used to fix the femoral stem prostheses in position. With each of the femoral stem prostheses disclosed in U.S. Pat. No. 5,080,680 and application Ser. No. 07/673,367, filed Mar. 22, 1991, (both of which are incorporated herein by reference) there is a gap between the end of the preapplied cement mantle and the upper end of the centralizer. There is a possibility that, upon implantation of either of such prostheses, the new bone cement will not completely fill the gap and will leave a portion of the stem of the metal component immediately above the centralizer uncontacted by bone cement. The presence of any such uncontacted area could lead to osteolysis and eventual loosening and failure of the implanted prosthesis.